On the relationship of the oil/water interfacial tension and the spread of oil slick under ice cover

Oil-spill experiments were carried out to observe the behavior of oil under ice cover in NMRI ice model basin. Oil/water interfacial tension and contact angle of oil/ice/water interface were also measured, using ADSA (Axisymmetric Drop Shape Analysis) method. As a result, the authors figure out the following: The contact angle of the interface was 180deg., and on the assumption of this contact angle, the measured size of the oil slick under flat ice cover was almost equivalent to the size of a very large axisymmetric oil drop which shape obeys Laplacian equation. The authors also investigated the past research work of this field, and figured out that the so-called “net interfacial tension” was equal to the twice of oil/ice interfacial tension, under the same assumption of the contact angle described above. The net interfacial tension was first introduced by Yapa and Chowdhury (1989) but its theoretical meaning was not known. These results were successfully verified by the experiments.